Investigating the Emerging Neurotoxic Potential of Acetonitrile-d3 in a Zebrafish Model: Implications for Human Mental Health

Abstract

Acetonitrile-d3 is a commonly used solvent in the chemical and pharmaceutical industries. However, it has become a growing environmental pollutant with potential neurotoxic effects that are not well understood Ahmed et al [1]. The rise in industrial discharge containing acetonitrile-d3 raises concerns about its impact on aquatic ecosystems and vertebrate neurobiology. This is particularly concerning due to the compound’s capacity to disrupt ionic balance and impair neurotransmitterfunction. To address the knowledge gap regarding its adverse effects on neurobehavioral parameters, the current study used zebrafish (Danio rerio) as a model organism. Zebrafish share about 70% of their genetic makeup with humans and have similar genes linked to neurological disorders Howe et al [2]. In this study, adult zebrafish were exposed to acetonitrile-d3 at 150, 300, 500, and 700 ppm, alongside an unexposed control group and for each group, 3 zebrafish were used. The exposure period lasted for 96 hours. Next, a thorough set of behavioural tests was conducted, including the Novel Tank Diving Test (NTDT) to assess anxiety related vertical exploration, the T-maze test to evaluate spatial memory and decision-making, and the Light Dark Preference Test to measure anxiety, exploration, and depression-like states at 0, 3rd, and 7th days. The behavioural analysis showed that exposure to acetonitrile-d3 caused dose-dependent changes in zebrafish. At the lowest concentration (150 ppm), the fish displayed subtle behavioural changes, including slight hypoactivity and more frequent freezing episodes. However, at moderate to high doses (300–700 ppm), the fish exhibited significant anxiety-like behaviours, memory problems, social withdrawal, and a marked decrease in exploratory activity. Heat map activity and track-plot patterns showed less spatial engagement and more bottom-dwelling behaviour at higher exposure levels. These findings represent the first in vivo evidence of acetonitrile-d3’s neurotoxic potential in a vertebrate model. The study outcomes raise important environmental and public health concerns about the compound’s risks in occupational settings and the ecosystem. Given the widespread industrial use of this compound and its presence in wastewater, the data highlight an urgent need for regulatory reviews, environmental monitoring, and risk assessments related to acetonitrile-d3 contamination. Future research should include molecular, biochemical, and long-term behavioural studies to clarify the mechanisms and lasting effects on brain function, as well as exploring effective countermeasures to neutralise the neurotoxicity. This research provides valuable baseline data for understanding how a proposed pollutant can cause neurobehavioral toxicity and reinforces the zebrafish as a useful model for environmental neurotoxicology. Zebrafish can serve as a reliable model for screening the industrial neurotoxicants that may have adverse neuropsychiatric effects in humans.